1. Technical Field
The present invention relates to a virtual image display device such as a head mounted display that is used while being mounted on the head.
2. Related Art
In recent years, as a virtual image display device for enabling formation and observation of a virtual image such as a head mounted display, various head mounted displays that scan an image light and project an image on the retinas of the eyes are proposed (see JP-A-2007-178941 (Patent Literature 1), WO2009/041055 (Patent Literature 2), and JP-T-2007-537465 (Patent Literature 3)). In particular, a head mounted display configured “see-through” in order to superimpose image light for forming a virtual image and external light, which is light from the external environment, one on top of the other is proposed (see, for example, Patent Literature 1).
However, when a wearer, who is an observer, is, for example, near-sighted and needs to correct the eyesight using a device for visibility adjustment such as glasses to observe the external light, if a device for forming a virtual image is the device disclosed in any one of Patent Literatures 1 to 3, the wearer wears the device in addition to the glasses or the like. In such a case, since a space for the glasses is secured on the side of the device for image formation, the device for image formation needs to be increased in size. According to the increase in size, it is likely that the weight of the device for image formation increases, a load on the wearer increases when the wearer wears the device, and design of the external appearance of the device is limited.